Missouri began voting on a constitutional amendment defining marriage to be between a man and woman on August 3. A total of nine states, and as many as 12, will vote on similar amendments this year.

Missouri became the first of nine states to vote on a constitutional amendment to ban same-sex marriage on August 3 and the first state to hold such a vote since Massachusetts legalized same-sex marriage in May.

A recent poll showed that about 60 percent of Missouri voters support the amendment, reported the Associated Press.

Although Missouri is one of 37 states which already has a law banning same-sex marriages, called The Defense of Marriage Act, a constitutional amendment defining marriage to be between a man and a woman only, which elevate the law and reducing the possibilities of challenges.

Eight other states are scheduled to vote on a constitutional amendment including, Lousiana which will vote on Sept. 18. and Arkansas, Georgia, Kentucky, Mississippi, Montana, Oklahoma and Utah which are scheduled to vote on Nov. 2.

As many as 12 states will join the effort to protect traditional marriage if enough petition signatures are gathered to place the measure on the state ballots.

"What happens here in Missouri could have a tremendous impact on the rest of the nation's other elections,'' said Vicky Hartzler, spokeswoman for the group backing the amendment, the Coalition to Protect Marriage in Missouri. ''I'm hopeful we will be able to send a very strong, clear message from Missouri that here in the heartland, we value traditional marriage.''